Certain types of lighting emit light, such as white light, in a particular color temperature. White light may be characterized in terms of temperature. Color temperatures over 5,000K are considered cool colors, meaning they emit light in a bluish-white range, whereas lower color temperatures (typically 2,200-3,000K) are considered warm colors (emitting light in a yellowish white through red range). Currently with LEDs, if the color goes below 2,700K, the emitted light is amber, which does not provide for the preferred color in typical residential and commercial applications. At present there is a desire to emit light in the warm range with LEDs which themselves emit light at below 2,700K.
In addition, the present invention is directed to meeting a desire to have light emitted preferably by LEDs encased in flexible strips. Such flexible strip lighting can be used in a variety of applications, such as but not limited to commercial displays, under cabinets, cove/soffit, and for safety purposes (such as aisle lighting). Flexible strips permit easy installation and avoid the need to deal with stringing and interconnecting the lights and the flexible strips allow such interconnection to be in place in advance, freeing the installer (or de-installer) to lay strips instead of individual lights.
This strip lighting is particularly desirable in commercial settings, where lights are installed and uninstalled frequently, particularly in displays which have short installation durations and the need to install is under time pressures.
In many of these circumstances, the color of the light is particularly important. For example, under cabinet lighting in certain commercial environments needs to be bright white, whereas cove/soffit lighting might need to be warmer color temperatures. Such flexible strips can potentially satisfy these color and installation needs, so long as the color of the LEDs can be adjusted from flexible strip to flexible strip in the production process.
Currently the main and only way to effect color temperature of LEDs is either via phosphor directly placed on the LED chip or via remote phosphor layers that are used as lenses over blue LEDs. Such a device may not be cost effective to manufacture. Another issue with the remote phosphor is aesthetics; when the light is off, it appears bright yellow or orange depending on the color temperature of the fixture.
Prior to the present invention, the use of LED flexible strips has been limited to the color temperature offered by the LED chip and incorporating remote phosphor solutions is both impractical mechanically speaking as well as cost prohibitive. The costs accrue from manufacture of the strips, the costs associated with the need to dissipate heat from the strips, and the costs to assemble and install the strips. In short, the present invention includes a novel approach so as to make the assembly of such devices more readily usable and economic in commercial environments.